Short- and medium-range order in Se-Ge glassy systems (I) effect of composition

Hafiz, M.M.; Hammad, F.H.; El-Kabany, N.

doi:10.1016/0921-4526(93)90130-x

Cited by 25 publications

(20 citation statements)

References 44 publications

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“…For Ge-Se glass system a study on the bond angle and the nearest neighbor distances reveals its structure to be a tetrahedron [2,6,16,17]. Thus it can be concluded that the results of both the theoretical methods employed here for studying the phonon dispersion in the glass system Ge-Se are in good agreement with each other and at the same time it brings out the same features of the structural studies reported so far [17].…”

Section: Elastic Propertiessupporting

confidence: 84%

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Effect of germanium content on the medium range order and the vibrational analysis of Ge–Se chalcogenide glass system

Jayakumar¹,

Predeep²,

Unnithan³

2004

Physica Status Solidi (b)

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An attempt is made to explain the Medium Range Order in the chalcogenide glass system Ge x -Se 1-x by computing the radial distribution function, g(r) from the available data of the structure factor, S(q). The results obtained are compared with pioneer works. The above obtained value of g(r) together with the effective interatomic potential calculated from S(q) applying Rao -Joarder equation is used for studying the vibrational eigen frequencies of the system both in the transverse and longitudinal phonon modes. From the long wavelength limit of the phonon frequency spectrum, the elastic and the thermal properties are also estimated.

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Section: Elastic Propertiessupporting

confidence: 84%

“…, ρ 0 being the number density [2]. The presence of the MRO in the system Ge x Se 1-x is attributed [8,10,11] to the Ge atom as the pre peak is observed in Ge chalcogenides (Ge-Se and Ge-S).…”

Section: Radial Distribution Function and Medium Range Ordermentioning

confidence: 94%

Effect of germanium content on the medium range order and the vibrational analysis of Ge–Se chalcogenide glass system

Jayakumar¹,

Predeep²,

Unnithan³

2004

Physica Status Solidi (b)

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“…FIGURE 2 | The dependence of the mass density at room temperature ρmass for the GexSe 1− x system on the composition x and mean coordination number n = 2(1 + x). The results from the present work at ≃22°C are compared to those taken from Andonov (1982), Avetikyan and Baidakov (1972), Azoulay et al (1975), Bhosle et al (2012b), Borisova (1981), Feltz et al (1983), Feltz and Lippmann (1973), Guin et al (2002b), Hafiz et al (1993), Ito et al (1988), Loehman et al (1972), Ota et al (1978), Senapati and Varshneya (1995), Sreeram et al (1991b), and Yang et al (2013). The solid (black) curves are drawn as guides for the eye.…”

Section: Glass Synthesis and Characterizationmentioning

confidence: 96%

Topological Ordering and Viscosity in the Glass-Forming Ge–Se System: The Search for a Structural or Dynamical Signature of the Intermediate Phase

et al. 2017

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The topological ordering of the network structure in vitreous Ge x Se 1−x was investigated across most of the glass-forming region (0 ≤ x ≤ 0.4) by using high-resolution neutron diffraction to measure the Bhatia-Thornton number-number partial structure factor. This approach gives access to the composition dependence of the mean coordination number n and correlation lengths associated with the network ordering. The thermal properties of the samples were also measured by using temperature-modulated differential scanning calorimetry. The results do not point to a structural origin of the so-called intermediate phase, which in our work is indicated for the composition range 0.175(8) ≤ x ≤ 0.235(8) by a vanishingly small non-reversing enthalpy near the glass transition. The midpoint of this range coincides with the mean-field expectation of a floppy-to-rigid transition at x = 0.20. The composition dependence of the liquid viscosity, as taken from the literature, was also investigated to look for a dynamical origin of the intermediate phase, using the Mauro-YueEllison-Gupta-Allan (MYEGA) model to estimate the viscosity at the liquidus temperature. The evidence points to a maximum in the viscosity at the liquidus temperature, and a minimum in the fragility index, for the range 0.20 ≤ x ≤ 0.22. The utility of the intermediate phase as a predictor of the material properties in network glass-forming systems is discussed.

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“…The information presented therefore complements other experimental studies on the composition, temperature and pressure dependence of the structure of Ge-Se compounds. These studies include the application of conventional diffraction methods using neutrons [11,12], X-rays [13][14][15][16] or electrons [17,18] as a probe, anomalous X-ray scattering [19][20][21][22][23], extended X-ray absorption fine structure (EXAFS) [24,25], X-ray emission [26] and Raman [27][28][29][30] spectroscopy, and 77 Se solid state nuclear magnetic resonance methods [31].…”

Section: Introductionmentioning

confidence: 99%